title: Gold(I) complexes of tetrathiaheterohelicene phosphanes.
abstract: New tetrathia[7]helicene-based (7-TH-based) gold(I) complexes 6 and 7 have been readily prepared by reaction of the respective phosphine ligands 2 and 3 with Au(tht)Cl in a 1:1 and 1:2 molar ratio, respectively. These complexes have been fully characterized by analytical and spectroscopic techniques as well as quantum chemical calculations. The molecular structure of dinuclear complex 7 has been determined by single-crystal X-ray diffraction, showing a gold-gold interaction of 3.1825(3) Å and a significant contraction of the 7-TH total dihedral angle. Au(I) complex 7 displays luminescence emission at room and low temperature in diluted solution and in the solid state. Quantum chemical calculations show that the luminescence emission at room temperature is primarily due to slightly perturbed fluorescence emission from purely ππ* excited states of the conjugated helicene scaffold. At 77 K phosphorescence emission is displayed as well. Preliminary studies on the use of 6 and 7 as catalysts in typical Au(I)-catalyzed cycloisomerizations have demonstrated the reactivity of these systems in the intramolecular allene hydroarylations and the hydroxycarboxylation of allene-carboxylates.
authors.affiliation: Dipartimento di Chimica, Università degli Studi di Milano, via Golgi 19, I-20133 Milan, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Cauteruccio
authors.forename: Annette
authors.initials: A
authors.lastname: Loos
authors.forename: Alberto
authors.initials: A
authors.lastname: Bossi
authors.forename: Maria Camila
authors.initials: MC
authors.lastname: Blanco Jaimes
authors.forename: Davide
authors.initials: D
authors.lastname: Dova
authors.forename: Frank
authors.initials: F
authors.lastname: Rominger
authors.forename: Stefan
authors.initials: S
authors.lastname: Prager
authors.forename: Andreas
authors.initials: A
authors.lastname: Dreuw
authors.forename: Emanuela
authors.initials: E
authors.lastname: Licandro
authors.forename: A Stephen K
authors.initials: AS
authors.lastname: Hashmi